android listView控件学习之一

android listView控件学习之一
1.基本应用:

1>res/layout/main.xml
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     >
    <ListView 
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:id="@+id/list_view"
     />
 </LinearLayout>
 2>listView 一般形式
 public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.main);               //ArrayAdapter为系统自带Adapter
                 Adapter myListAdapter  = new                         ArrayAdapter<String> (this,android.R.layout.simple_list_item_1, mStrings));
   
                 listView = (ListView) findViewById(R.id.list_view);
                }
 3.listView 设置成像checkboxes 多选方法.
 1>设置choice mode属性
 2>list用CHOICE_MODE_MULTIPLE mode.
 如下:
 public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);    setListAdapter(new ArrayAdapter<String>(this,
        
   listView.setItemsCanFocus(false);
     listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
   
  }
 4. listView 设置成像checkboxes 单选方法
 1>设置choice mode属性
 2>list用CHOICE_MODE_SINGLE
 public void onCreate(Bundle savedInstanceState) {
               setListAdapter(new ArrayAdapter<String>(this,
                 android.R.layout.simple_list_item_single_choice, GENRES));
        
               listView.setItemsCanFocus(false);
         listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
     }
 5. listView 自己定义Adapter 实现效果每行前面为图片后面紧跟文字.(imageView and textView)
 1>构造MyListAdapter类
 2>Adapter样式
 res/layout/list_item_icon_text.xml
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="horizontal" android:layout_width="fill_parent"
  android:layout_height="fill_parent"><ImageView android:id="@+id/icon" android:layout_width="48dip"
   android:layout_height="48dip" /><TextView android:id="@+id/text" android:layout_gravity="center_vertical"
   android:layout_width="0dip" android:layout_weight="1.0"
   android:layout_height="wrap_content" />
 </LinearLayout>
 3>引用方式
 public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.main); myListAdapter = new MyListAdapter(this);
 listView = (ListView) findViewById(R.id.list_view);
   listView.setAdapter(myListAdapter);
  }
 4>如何将自定义Adapter样式与View联系在一起.
 mInflater = LayoutInflater.from(context);
 View convertView = mInflater.inflate(R.layout.list_item_icon_text, null);
 5>重写getView()方法
 public View getView(int position, View convertView, ViewGroup parent) {
   // A ViewHolder keeps references to children views to avoid unneccessary
   // calls
   // to findViewById() on each row.
   ViewHolder holder; // When convertView is not null, we can reuse it directly, there is no
   // need
   // to reinflate it. We only inflate a new View when the convertView
   // supplied
   // by ListView is null.
   if (convertView == null) {
    convertView = mInflater.inflate(R.layout.list_item_icon_text, null);  // Creates a ViewHolder and store references to the two children
    // views
    // we want to bind data to.
    holder = new ViewHolder();
    holder.text = (TextView) convertView.findViewById(R.id.text);
    holder.icon = (ImageView) convertView.findViewById(R.id.icon);  convertView.setTag(holder);
   } else {
    // Get the ViewHolder back to get fast access to the TextView
    // and the ImageView.
    holder = (ViewHolder) convertView.getTag();
   } // position = position % DATA.length; //实现向下循环
   // Bind the data efficiently with the holder.
   holder.text.setText(DATA[position]);
   holder.icon.setImageBitmap((position & 1) == 1 ? mIcon1 : mIcon2); return convertView;
  }static class ViewHolder {
   TextView text;
   ImageView icon;
  }
 }